Decoder: Delete node from st if lt and st point to same

If lt_list and st_list point to same node then delete it from st.
If there is error while adding a node in bottom field of lt_list (top is
already added) then this node will be pointed by st_list also. So we need
to remove it from st_list

bug: 73552574
Test: poc before/after on Android N security branch
Change-Id: I95304c242c5854b18c5c7220d114ce6215760124
(cherry picked from commit f312a1d3)